1. Field of the Invention
The present invention relates to spacecraft instrumentation. More specifically, the present invention relates to systems and techniques for monitoring the temperature of scan mirrors used in connection with spacecraft instruments.
2. Description of the Related Art
Scan mirrors are often used in spacecraft to redirect energy received by the craft from a surface to an onboard sensor. The sensor is typically part of an instrument which generates data from the sensor readings. The data is stored, processed onboard and/or transmitted to earth for processing.
Some spacecraft components rotate for stabilization, scanning or other purposes. Scan mirrors on spacecraft in orbit around planetary and astral bodies near the sun experience temperature variations during rotation due to the effects of solar radiation and deep space. This causes distortions in images reflected by the mirror. Accurate knowledge of the mirror temperature is of paramount importance in calibrating data generated by the instrument under such circumstances.
An alternate approach for detecting the temperature of the mirror involves the location of a temperature sensor on the scanning mirror. This is only practical when the mirror oscillates instead of rotates as the extraction of electrical signals from the sensor is not possible inasmuch as any wires would experience a considerable amount of stress due to the scanning motion of the mirror.
To circumvent this problem, a radio transmitter has been used with the temperature sensor. However, this approach is costly, may impede the operation of the mirror and the radio signal may interfere with one or more of the instruments or other systems located on the spacecraft.
Hence, a need remains in the art for a low cost, effective system and/or technique for accurately measuring the temperature of a scanning mirror without interfering with the operation of the mirror or other instruments and systems on the spacecraft.